Fuel injection nozzles

ABSTRACT

A fuel injector nozzle including an electromagnetically operable valve which controls fuel flow along a fuel tube to an outlet. The fuel tube forms a flow restrictor and can be removed from and replaced in the nozzle without disturbing any part of the valve.

United States Patent Jackson I451 Aug. 22, 1972 FUEL INJECTION NOZZLES [72] Inventor:

Harold Ernest Jackson, Panorama Vicarage Road, Plympton, St. Mary, England Filed: June 26, 1970 Appl. No.: 50,257

Foreign Application Priority Data June 27, 1969 Great Britain ..32,53l/69 US. Cl. ..239/407, 239/4195, 239/4285, 239/585 Int. Cl. ..B05b 7/12 Field of Search ..239/407, 408, 419.5, 428.5, 239/533, 585

[56] References Cited UNITED STATES PATENTS 1,627,727 5/1927 Charter ..239/585 X 2,388,508 11/1945 Timpson ..239/428.5

FOREIGN PATENTS OR APPLlCATlONS 1,308,030 9/ 1962 France ..239/407 Primary Examiner-M. Henson Wood, Jr. Assistant Examiner-Edwin D. Grant Attomey-Holcombe, Wetherill & Brisebois [57] ABSTRACT A fuel injector nozzle including an electromagnetically operable valve which controls fuel flow along a fuel tube to an outlet. The fuel tube forms a flow restrictor and can be removed from and replaced in the nozzle without disturbing any part of the valve.

10 Claims, 4 Drawing Figures FUEL INJECTION NOZZLES This invention relates to fuel injector nozzles for use i in fuel injection systems for internal combustion engines and, in particular, to nozzles which are operable to discharge fuel intermittently.

The injector nozzles are usually positioned to discharge fuel into the intake manifold system of the internal combustion engine downstream of the throttle valve: each nozzle may, for example be positioned to discharge fuel into a respective branch pipe leading from the intake manifold to an engine cylinder. Alternatively, each nozzle may be positioned to discharge fuel directly into a respective engine cylinder downstream of the cylinder intake valve.

In some systems the injector nozzles are of the socalled open type and, in operation, discharge fuel continuously. Other systems however, operate to discharge fuel intermittently and to thisend each injector nozzle may include a fuel flow control valve operable in response to electrical signals generated by a control unit forming part of the system. The control unit determines the frequency at which the injector nonles operate and the length of time for which the nozzles discharge fuel, and in some systems, thecontrol unit adjusts these operating characteristics in dependence on variations in an engine operating parameter. Alternatively, or in addition, the system may operate to adjust the fuel supply to the nozzles in response to variations in an engine operating parameter.

The present invention provides a fuel injector nozzle including a fuel tube which is located within an outer jacket and which has a fuel outlet aligned with an outlet orifice in the outer jacket, and an electromagnetically operable interrupter valve including a valve member movable between open and closed positions to control fuel flow through the fuel tube, the outer jacket including at least one vent through which air is drawn into the jacket during fuel flow through the outlet orifice.

Preferably the fuel tube is a constant fine-bore tube which forms a fuel flow restrictor. Preferably also the fuel tube is removable from the nozzle without disturbing the interrupter valve.

The outer jacket may include at least one vent positioned to admit air at a point intermediate the ends of the fuel tube. Alternatively, or in addition, the outer jacket may include at least one vent positioned to admit air at a point downstream of the fuel outlet: this point may also be downstream of the outlet orifice.

By way of example, fuel injector nozzles constructed in accordance with the invention will be described with reference to the accompanying drawings, in which:

FIG. 1 is a cross-section of one form of nozzle;

FIG. 2 is a view on the line 11-11 of FIG. 1;

FIG. 3 is a cross-section of another form of nozzle, and

FIG. 4 illustrates the use of nozzles in accordance with the invention in a fuel injection system.

The nozzle shown in FIGS. 1 and 2 has an outer casing 130 in one end of which is located a stop member 131 which extends into the central passage of a spoolshaped member 132 within the casing. A fuel inlet 140 is defined in the stop member 131 and communicates via a passage 141 in the stop member with the interior of a tubular valve member 142 also partly located in the central passage of the spool-shaped member 132. The valve member 142, or at least a portion of the valve member within the spool 132 is formed of a magnetizable material and a solenoid 151 is wound on the spool and connected to electrical terminals 133 on the casing 130. One of the terminals 133 together with one of the electrical leads 134 to the solenoid 151 is shown in FIG. 2.

The interior of the valve member 142 communicates, through ports 143 in the valve member wall with a chamber 144 formed in the outer casing 130. A spring 145, located within the valve member 142 and seated against the stop member 131 biases the valve member against a seating 146, in which position communication between the chamber 144 and a fuel tube 147 is cut off by the valve member. The fuel tube 147 extends within an outer jacket 149 which is an extension of the outer casing 130. The jacket 149 is closed at its distal end by a tip in which is formed an outlet orifice 148 with which the end of the fuel tube 147 is aligned, as shown in FIG. 1. The fuel tube 147 is a stainless steel tube having a small bore diameter, for example a bore diameter of several ten thousandths of an inch. The interior of the jacket 149 is vented to atmosphere through ports 150 in the jacket wall.

In use of the nozzle, the fuel inlet is connected to receive fuel from a fuel supply conduit of a fuel injection system, and the outlet orifice 148 is positioned to discharge into the intake manifold system of an internal combustion engine. The solenoid 151 is connected through the terminals 133 and leads 134 to an electrical pulse generating unit.

When the solenoid 151 is not energized, the valve member 142 is biased by thespring 145 against the seating 146 as shown in FIG. 1 and prevents fuel flow from the fuel inlet 140 to the fuel tube 147. When, however, the solenoid 151 is energized by an electrical pulse, magnetic forces act on the magnetizable portion of the valve member 142 and move the valve member away from the seating 146. Fuel then flows from the inlet 140 through the passage 141, the parts 143 in the valve member, and the chamber 144 into the fuel tube 147 and is discharged through the outlet orifice 148. At the same time, air is drawn into the jacket 149 from atmosphere through the ports 150 and serves to atomize the fuel stream emerging from the fuel tube 147 and passing through the outlet orifice 148. The venting of the interior of the jacket 149 to atmosphere serves the additional purpose of ensuring that the depression existing in the intake manifold in which the nozzle outlet orifice 148 is located does not affect fuel flow through the tube 147.

The fine bore fuel tube 147 acts as a flow restrictor and is substantially the only restriction to fuel flow through the nozzle when the valve member 142 is in the open position. The tube 147 is flow-rated during assembly of the nozzle and, when a system includes a plubody portion includes a fuel inlet 140, a tubular valve member 142 biased by a spring 145 against a seating 146, and a solenoid 151. The valve member 142 controls fuel flow from the inlet 140 to a fuel tube 147 located in the nozzle portion of the injector to discharge fuel through an outlet orifice 148 in the nozzle tip 135.

As in the nozzle shown in FIG. 1, the fuel tube 147 extends within an outer jacket 149 the interior of which is vented to atmosphere through ports 150. In this case, however, the jacket 149 is not merely an extension of the outer casing 130 of the nozzle but is screwed onto the outer casing as indicated at 152. This enables the outer jacket 149 and the accompanying nozzle tip 135 to be removed to expose the fuel tube 147. The fuel tube 147 is located in a central bore in a block 153 which is a continuation of, but separately formed from the valve seating member 146. The block 153 is held against the valve seating member 146 by a spring 154 seated, as shown in FIG. 4, between a step formed in the jacket 149 and a projection formed on the block 153. Removal of the outer jacket 149 thus releases the block 153 and fuel tube 147 so that the fuel tube 147 can be replaced if necessary. This enables the characteristics of the nozzle to be readily adapted to suit different systems since it is necessary only to replace the fuel tube 147 by another tube having a different flow rating. It will be noted that, since the fuel tube 147 is completely separate from the nozzle valve 142, 146 the latter will be unaffected by any replacement of the fuel tube.

The nozzle shown in FIG. 3 also has additional vent ports 154 formed in the nozzle tip 135. During operation of the nozzle, atmospheric air is drawn through both sets of vent ports 150, 154: the first set of vent ports 150 serves to atomize the fuel stream emerging from the fuel tube 147 and the second set of vent port 154 introduces an air stream which impinges on the fuel passing through the outlet orifice 148 and effects further atomization. It has been found that the use of two sets of vent ports 150, 154 positioned as shown in FIG. 3 results in particularly efficient atomization of the fuel discharged by the nozzle.

FIG. 4 illustrates the use of nozzles 200 constructed in accordance with the invention in a fuel injection system. The nozzles 200 may, for example be of the type shown in FIG. 1 or FIG. 3. The system includes a fuel tank 201 from which fuel is drawn by any suitable form of pump 202 and supplied to a pressurizing device 203. The device 203 pressurizes fuel independence on engine air intake as indicated by the dotted line connection 204 to the engine air intake conduit 205 and the fuel is then supplied to the injector devices 200. Excess fuel from the pressurizing device 203 is returned to the fuel tank 201 via a relief valve 206, and excess fuel from the nozzles 200 is also returned to the tank via a conduit 207. The system also includes an injector control device 208 which is responsive to engine air intake as indicated by the dotted line connection 209 to the air intake conduit 205 and generates electrical pulses at regular time intervals but adjusts the length of the pulses as engine air intake varies. These pulses are applied to the injector nozzles 200 so that the latter operate intermittently to discharge fuel, being opened at regular time intervals and remaining open for a length of time de endent on ingine air intake.

ystems of t e type shown In FIG. 4 are described m greater detail in my copending United States Patent application No. 46201 filed 15th June, 1970. It will be appreciated, however, that injector devices constructed in accordance with the invention are not restricted to use in systems of this type, and may be used in any system in which injector devices are operated in response to electrical control signals.

I claim:

1. A fuel injector nozzle including a fuel tube assembly comprising a fuel tube holder from which extends a fuel tube having a fuel outlet; an electromagnetically operable interrupter valve comprising a valve seat and a valve member which is movable into and out of engagement with the valve seat to control fuel flow through the fuel tube; an outer jacket surrounding the fuel tube and having an outlet orifice aligned with the fuel outlet, seating means formed in said outer jacket, and resilient means located on said seating means and engaging the fuel tube holder to bias the holder against the interrupter valve, the outer jacket and the fuel tube assembly being removable from and replaceable in the nozzle without disturbing the interrupter valve member and the interrupter valve seat.

2. A nozzle as claimed in claim 1, in which the fuel tube is a constant fine-bore tube which forms a fuel flow restrictor.

3. A nozzle as claimed in claim 1, in which the interrupter valve includes a solenoid and the valve member is an elongated member movable into and out of the solenoid.

4. A nozzle as claimed in claim 1, in which the interrupter valve is located upstream of the fuel tube.

5. A fuel injector nozzle as claimed in claim 1, including an outer jacket surrounding the fuel tube and having an outlet orifice aligned with the fuel outlet and at least one vent through which air is drawn into the jacket during fuel through the outlet orifice.

6. A nozzle as claimed in claim 5, in which the outer jacket is removable from the nozzle.

7. A nozzle as claimed in claim 6, in which the outer jacket is in screw-threaded engagement with the main body of the nozzle.

8. A nozzle as claimed in claim 5, in which the outer jacket includes at least one vent positioned to admit air at a point intermediate the ends of the fuel tube.

9. A nozzle as claimed in claim 5, in which the outer jacket includes at least one vent positioned to admit air at a point downstream of the fuel outlet.

10. A nozzle as claimed in claim 9, in which the vent positioned to admit air downstream of the fuel outlet is positioned to admit air at a point downstream of the outlet orifice.

UNITED STATES- PATENT OFFICE R CERTIFICATE OF CORREC'HQN Patent N5. 3,685,742 Dated August 22, 1972 HAROLD ERNEST JACKSON It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as, shown below:

[73] Assignee: PETROL INJECTION LIMITED,

Plymouth, Devon, England Signed and sealed this 3rd d a y of April 1973.

(SEAL) Attest:

EDWARD M.FLETGHER,JR. 2 ROBERT VGOTTSCHALK Attesting Officer Commissioner of Patents FORM PO-1050 (10-69) USCOMM-DC 6O376-P69 U.5. GOVERNMENT PRINTING OFFICE: I969 O3$6'334 

1. A fuel injector nozzle including a fuel tube assembly comprising a fuel tube holder from which extends a fuel tube having a fuel outlet; an electromagnetically operable interrupter valve comprising a valve seat and a valve member which is movable into and out of engagement with the valve seat to control fuel flow through the fuel tube; an outer jacket surrounding the fuel tube and having an outlet orifice aligned with the fuel outlet, seating means formed in said outer jacket, and resilient means located on Said seating means and engaging the fuel tube holder to bias the holder against the interrupter valve, the outer jacket and the fuel tube assembly being removable from and replaceable in the nozzle without disturbing the interrupter valve member and the interrupter valve seat.
 2. A nozzle as claimed in claim 1, in which the fuel tube is a constant fine-bore tube which forms a fuel flow restrictor.
 3. A nozzle as claimed in claim 1, in which the interrupter valve includes a solenoid and the valve member is an elongated member movable into and out of the solenoid.
 4. A nozzle as claimed in claim 1, in which the interrupter valve is located upstream of the fuel tube.
 5. A fuel injector nozzle as claimed in claim 1, including an outer jacket surrounding the fuel tube and having an outlet orifice aligned with the fuel outlet and at least one vent through which air is drawn into the jacket during fuel flow through the outlet orifice.
 6. A nozzle as claimed in claim 5, in which the outer jacket is removable from the nozzle.
 7. A nozzle as claimed in claim 6, in which the outer jacket is in screw-threaded engagement with the main body of the nozzle.
 8. A nozzle as claimed in claim 5, in which the outer jacket includes at least one vent positioned to admit air at a point intermediate the ends of the fuel tube.
 9. A nozzle as claimed in claim 5, in which the outer jacket includes at least one vent positioned to admit air at a point downstream of the fuel outlet.
 10. A nozzle as claimed in claim 9, in which the vent positioned to admit air downstream of the fuel outlet is positioned to admit air at a point downstream of the outlet orifice. 